The present invention relates to improvements in torque transmitting devices, and more particularly to improvements in internally toothed torque transmitting devices. Still more particularly, the invention relates to improvements in torque transmitting devices which can be utilized with advantage in torsionally stiff engine couplings for hydrostatic systems as well as many additional purposes.
U.S. Pat. No. 3,861,172 (granted Jan. 21, 1975 to Heinz George Symann "Coupling for combustion engine") discloses an internally toothed torque transmitting device (called flange) which can be used to transmit torque to a pinion having an annulus of crowned external teeth. The patented torque transmitting device and the pinion can move relative to each other in the radial direction and can also transmit torque in positions in which their axes are inclined relative to each other. The torque transmitting device of Symann employs a metallic disc of one piece with an internal sleeve which surrounds an internal gear having axially parallel teeth movable into and out of mesh with the crowned teeth of the pinion. A drawback of the patented torque transmitting device is that it is rather heavy, bulky and expensive. Furthermore, the thickness of the disc-shaped metallic portion of the patented device is directly proportional to the magnitude of torque which can be transmitted to or from the pinion.
It is also known to provide the torque transmitting device of Symann with reinforcing ribs each extending radially from a centrally located hub to a rim which is spaced apart from and surrounds the hub. The radially extending ribs are of one piece with a relatively thin washer-like part which extends between the hub to the rim and one side of which is of one piece with the ribs. A drawback of such devices is that they cannot be utilized for transmission of torque between a piston type combustion engine and a driven part. The magnitude of torque which is being transmitted by the output element of a piston type engine to a flywheel and thence to the aforementioned torque transmitting device employing a washer-like disc and radially extending reinforcing ribs of one piece with one side of the disc will fluctuate whenever a piston of the engine completes its forward stroke and proceeds to perform a return stroke as well as when a piston completes its rearward stroke and begins the next-following forward stroke. Such fluctuations of transmitted torque cause the reinforcing ribs to undergo very pronounced dynamic bending stresses. The only presently known remedy is to increase the dimensions of the reinforcing ribs and of the entire torque transmitting device. Thus, it is necessary to produce and store a number of larger and smaller torque transmitting devices in order to ensure that the selected device will be capable of withstanding the aforediscussed dynamic bending stresses.